1. Field of the Invention
The present invention relates to a frequency reference for an oscillation circuit, and in particular, to a frequency reference formed from standard components internal to an integrated circuit that utilizes the thermal time constant of silicon to maintain constant frequency oscillation.
2. Description of the Related Art
Oscillators are well known in the art of solid state electronics. Oscillator circuits producing a constant frequency signal are extremely useful for performing vital system functions such as clocking. Any constant frequency oscillator requires: 1) a source of power; 2) an amplifying device; and 3) some form of resonant circuit to maintain the frequency of output.
Solid-state, constant-frequency oscillator circuits formed from semiconductors must include a frequency reference. This frequency reference enables the oscillator to maintain a constant frequency output. In many solid-state circuits, the source of this frequency reference is a separate crystal having an intrinsic vibrational frequency. Such a circuit utilizes the crystal's inherent vibration to generate a constant frequency output signal.
Unfortunately, incorporating an external component such as a crystal into an IC creates additional complexity and expense in the manufacturing process. Therefore, there is a need in the art for a structure formed from standard integrated circuit components that is capable of maintaining the output of an oscillator at a regular frequency.